I live near the Quays in Gloucester but we're in the process of moving to Tewkesbury.
There's a giant shopping village place opening in Tewkesbury next year (next to the motorway junction) which is going to be like the Quays but even bigger and better (largest in the south west I think?). Bredon is very beautiful with lots of walks, but close to Tewkesbury so could give you the best of both worlds. Tewkesbury also has lots of events - like the big Medieval festival every July and it's quite a pretty town.
Tewkesbury floods so you have to be very careful where you live if you move to Tewkesbury itself. But in the right spot you won't flood and you won't ever get cut off because there's motorway access as well as all the A-roads.
Personally I wouldn't want to live in Dursley, there's some dodgy parts and there's not much there. It also feels like quite a long way from hospitals, shops, good schools. Stroud might be a good interim option. Hilly and lots of good walks around there but has its own cinema, hospital etc and there are some decent schools too.
The Forest of Dean is always popular but it feels quite remote and the traffic to get in and out can be a giant ball ache. Issues with snow, flooding etc tend to affect the Forest more, even if it's just cutting off access because of the roads.
Gloucester itself I wouldn't bother with either. It's getting more and more built-up with traffic issues and there's nothing special about it. The surrounding areas are way nicer.
Cheltenham is probably the best shopping area with lots of boutiques, restaurants etc but it's expensive and I find it crowded. Bishops Cleeve is a lovely area, small village location midway between Cheltenham and Tewkesbury with lots of walks and green spaces. That's a good shout too.
Sorry, bit of a brain dump there haha! I'm actually a Londoner but I moved here 20 years ago and I bloody love the place.